Foliar ZnSe co-biofortification in wheat grains: Proteomic insights into nutritional enhancement and molecular...

Human deficiencies of zinc (Zn) and selenium (Se) primarily originate from their low concentrations in staple crops. We hypothesized that optimizing foliar ZnSe application would achieve ZnSe co-biofortification. This hypothesis was tested through field and soil culture experiments with proteomic analysis. Co-application induced antagonistic interactions between Zn and Se, but optimization of foliar concentration (0.4 % ZnSO₄·7H₂O + 0.0021 %-0.0024 % Na₂SeO₃) compensated for this antagonism, enhancing grain Zn and Se accumulation while maintaining Se concentration below the toxic threshold (<1.0 mg·kg^-1). This approach shifted Se speciation to 96.7 % organic forms, met daily Zn and Se intake requirements for adults from both flour and whole grain consumption. Proteomic analysis identified differentially expressed proteins involved in selenium, sulfur, and amino acid metabolism in response to ZnSe accumulation. Therefore, we established a field-validated, cost-effective ZnSe co-biofortification strategy readily integrated into conventional wheat production systems, offering a practical solution to alleviate human micronutrient deficiencies.